rhombohedral packing

rhombohedral packing

[¦räm·bō¦hē·drəl ¦pak·iŋ]
(crystallography)
The tightest manner of systematic arrangement of uniform solid spheres in a clastic sediment or crystal lattice, characterized by a unit cell of six planes passed through eight sphere centers situated at the corners of a regular rhombohedron. Also known as rhombohedral close packing.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.